CVE-2021-1242Network attack vector

Phishing via shared file-name rendering

Published Jan 13, 2021 · Updated Nov 12, 2024

A character-rendering vulnerability in Cisco Webex App before 40.12.0.17293 allows remote attackers to alter shared file names in messaging. The client mishandles character rendering when a shared file name is displayed, letting an attacker change its apparent text. Exploitation requires sharing a crafted file in the messaging interface and user viewing of the message; the bounded impact is phishing or spoofing through misleading names, not code execution.

CVSS severity4.3
Medium
EPSS probability1.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A character-rendering vulnerability in Cisco Webex App before 40.12.0.17293 allows remote attackers to alter shared file names in messaging. The client mishandles character rendering when a shared file name is displayed, letting an attacker change its apparent text. Exploitation requires sharing a crafted file in the messaging interface and user viewing of the message; the bounded impact is phishing or spoofing through misleading names, not code execution.

The record

CVE
CVE-2021-1242
Published
Jan 13, 2021
Updated
Nov 12, 2024
Vendor
ClamAV
Product
Webex App
Classifications
CWE-450, T1036
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 13, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 12, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Webex Appversion=n/a

Published CVSS scores

4.3CiscoCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-450Improper Handling of Unicode Encoding
T1036Masquerading

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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